Impact of sleep disorder treatment on fatigue in multiple sclerosis

Background: We recently reported that sleep disorders are significantly associated with fatigue in multiple sclerosis (MS). Objective: The objective of this paper is to assess the effects of sleep disorder treatment on fatigue and related clinical outcomes in MS. Methods: This was a controlled, non-randomized clinical treatment study. Sixty-two MS patients completed standardized questionnaires including the Fatigue Severity Scale (FSS), Multidimensional Fatigue Inventory (MFI), Epworth Sleepiness scale (ESS) and Pittsburgh Sleep Quality Index (PSQI), and underwent polysomnography (PSG). Patients with sleep disorders were offered standard treatment. Fifty-six subjects repeated the questionnaires after >= three months, and were assigned to one of three groups: sleep disorders that were treated (SD-Tx, n=21), sleep disorders remaining untreated (SD-NonTx, n=18) and no sleep disorder (NoSD, n=17). Results: FSS and MFI general and mental fatigue scores improved significantly from baseline to follow-up in SD-Tx (p <0.03), but not SD-NonTx or NoSD subjects. ESS and PSQI scores also improved significantly in SD-Tx subjects (p <0.001). Adjusted multivariate analyses confirmed significant effects of sleep disorder treatment on FSS (-0.87, p = 0.005), MFI general fatigue score (p = 0.034), ESS (p = 0.042) and PSQI (p = 0.023). Conclusion: Treatment of sleep disorders can improve fatigue and other clinical outcomes in MS.